Methods and Systems for Enabling Feedback in Wireless Communication Networks

• US 20080069031A1
• Filed: 06/22/2005
• Published: 03/20/2008
• Est. Priority Date: 06/22/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Zhang, Hang, Tong, Wen, Ma, Jianglei, Zhu, Peiying, Fong, Mo-Han
• Granted Patent: US 8,116,262 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0478 Special codebook structures directed to feedback optimisation
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0619 using feedback from receiving side feedback signaling for adaptive modulation/coding H04L1/0001
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0673 using feedback from receiving side
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0028 Variable division signaling therefor H04L5/0092
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/54 based on quality criteria
• CPC Class Codes: H04W 74/06 using polling

Abstract

Aspects of the present invention provide additional MAC functionality to support the PHY features of a wireless communication system framework. The additional MAC functionality aids in enabling feedback from wireless terminals to base stations. In some aspects of the invention the feedback is provided on an allocated feedback channel. In other aspects of the invention the feedback is provided by MAC protocol data units (PDU) in a header, mini-header, or subheader. The feedback may be transmitted from the wireless terminal to the base station autonomously by the wireless terminal or in response to an indication from the base station that feedback is requested. Aspects of the invention also provide for allocating feedback resources to form a dedicated feedback channel. One or more of these enhancements is included in a given implementation. Base stations and wireless terminals are also described upon which methods described herein can be implemented.

Claims

1. A method in a wireless terminal for enabling feedback in an uplink transmission of a communication system from the wireless terminal to a base station, the method comprising:

the wireless terminal transmitting feedback information in a MAC feedback protocol data unit (PDU) of a data frame, the feedback information comprising feedback type and feedback content, wherein the wireless terminal transmitting feedback information is performed subsequent to the wireless terminal autonomously transmitting on a dedicated feedback channel an indication that the wireless terminal has feedback information to transmit.

2. The method of claim 1 further comprising the wireless terminal receiving an allocated location in an information element of an uplink resource allocation portion of the data frame for transmitting feedback information in a MAC feedback protocol data unit (PDU), the allocated location received in response to the autonomous indication transmitted by the wireless terminal that the wireless terminal has feedback information to transmit.

4. The method of claim 1, wherein the wireless terminal transmitting feedback information in a MAC feedback PDU comprises using one of a group of feedback formats consisting of a feedback header, a reduced-size feedback header, and a feedback subheader.

13. The method of claim 4, wherein the feedback format is the feedback header comprising a following format:

CID Header Encryption Inclusion Feedback Feedback Type = 1 Control = 1 Type = 0 Indication type content (1 bit) (1 bit) (1 bit) (1 bit) (4 bits) (8 bits) Feedback content (8 bits) Basic Connection Identification (8 bits) Basic Connection Identification Header Check Sequence (8 bits) (8 bits)

14. The method of claim 4, wherein the feedback format is the feedback header comprising a following format:

CID Header Encryption Inclusion Feedback Feedback Type = 1 Control = 1 Type = 0 Indication type content (1 bit) (1 bit) (1 bit) (1 bit) (4 bits) (8 bits) Feedback content (8 bits) Feedback content (8 bits) Feedback content (8 bits) Header Check Sequence (8 bits)

15. The method of claim 4, wherein the feedback format is the reduced-size feedback header comprising a following format:

Header Encryption Type = 1 Feedback Feedback Header Type = 1 Control = 1 (1 bit) type content Check (1 bit) (1 bit) (4 bits) (8 bits) Sequence (8 bits)

16. The method of claim 4, wherein the feedback format is the feedback subheader comprising a following format:

Name Size in bits Description Feedback Type 4 Type of feedback Feedback Content 12

31. A wireless terminal in a MIMO enabled OFDM communications system adapted to perform the method of claim 1.

32. The method of claim 1, wherein the wireless terminal transmitting feedback information in a MAC layer feedback protocol data unit (PDU) comprises an indication for additional uplink resources to be allocated to the wireless terminal to transmit additional feedback information.

3. A method in a wireless terminal for enabling feedback in an uplink transmission of a communication system from the wireless terminal to a base station, the method comprising:

the wireless terminal receiving an indication of a type of feedback information being requested by the base station in an information element in an uplink resource allocation portion of a data frame;

in response to receiving the information element, the wireless terminal transmitting feedback information in a MAC feedback protocol data unit (PDU) of the data frame, the feedback information comprising feedback type and feedback content.

5. A method in a wireless terminal for enabling feedback in an uplink transmission of a communication system from the wireless terminal to a base station, the method comprising:

the wireless terminal receiving a polling indication of a type of feedback information requested by the base station, the polling indication being an information element in an uplink resource allocation portion of a data frame;

in response to receiving the polling indication, the wireless terminal transmitting feedback information in a feedback channel of the data frame.

6. The method of claim 5, wherein the wireless terminal transmitting feedback information in a feedback channel comprises transmitting in a dedicated feedback channel.

7. The method of claim 5, wherein the wireless terminal transmitting feedback information in a feedback channel comprises transmitting in a temporarily allocated feedback channel.

8. A method in a base station for enabling feedback in an uplink transmission of a communication system from a wireless terminal to a base station, the method comprising:

the base station transmitting a location in a data frame for allocating requested feedback information to be received by the base station, the base station transmitting the location in an information element in an uplink resource allocation portion of the data frame.

30. A base station in a MIMO enabled OFDM communications system adapted to perform the method of claim 8.

9. A method in a base station for enabling feedback in an uplink transmission of a communication system from a wireless terminal to a base station, the method comprising:

the base station transmitting an indication of a type of feedback information requested by the base station, the indication comprising an information element in an uplink resource allocation portion of a date frame.

10. The method of claim 9, wherein the base station transmitting an indication of a type of feedback information requested by the base station further comprises:

the base station transmitting;

a) a total number of feedback resource allocations for a data frame;

b) an indication if feedback resources are to be dedicated;

c) for each feedback resource allocation of the total number of feedback resource allocations, the base station transmitting;

i) an identifier for the wireless terminal for which the feedback resource allocation is occurring;

ii) if the feedback resource is currently not released, the base station transmitting;

an indication of feedback type requested by the base station and a location of a subsequent data frame with reference to the data frame indicating when feedback information requested by the base station will be received on an allocated feedback resource;

if feedback resources are to be dedicated as a part of this method as indicated above, allocating a feedback resource by transmitting location information for the feedback resource.

11. The method of claim 10, wherein the base station transmitting the indication in the format of an information element comprises transmitting a feedback polling information element.

12. The method of claim 11, wherein the feedback polling information element comprises a following format:

Syntax Size in bits Notes Feedback polling IE( ) {  

Extended UIUC 4 Identifies type of IE  

Length 8 Length of the message in bytes  

Num Allocations 4 Number of allocations in this IE  

Dedicated UL 1 0;

No dedicated UL resource is  

Allocation Included allocated in feedback polling IE. BS should allocate UL resource through the UL map IE at each designated transmitting frame defined by this IE. 1;

Dedicated UL resource is included in the IE  

Reserved 3 Set to zero  

for (i = 0;

i <

Num  

Allocations ;

i++) {  

Basic CID 16 Basic ID of the polled MSS  

Allocation Duration The allocation is valid for 10 ×

2d  

(d) frame starting from the frame defined by Frame offset If d=0b000, the pre-scheduled Feedback header transmission is released If d=0b111, the pre-scheduled Feedback header transmission shall be valid until the BS commands to release it  

If (d !=

     000){  

 

Feedback type 4  

 

Frame offset 6 The offset (in units of frames) from the current frame in which the first feedback header shall be transmitted on the allocated UL resource. The start value of frame offset shall be 1  

 

Period (p) 2 The UL resource region is dedicated to the MS in every 2^p frame  

 

If (Dedicated UL Allocation Included ==

     1){  

 

UIUC 4  

 

OFDMA symbol 8  

 

offset  

 

Subchannel offset 7  

 

Duration 3 In OFDMA slots  

 

Repetition coding 2 0b00 - No repetition coding  

 

indication 0b01 - Repetition coding of 2 used 0b10 - Repetition coding of 4 used 0b11 - Repetition coding of 6 used  

 

}  

 

}  

}  

Padding bits }

17. A method for dynamically allocating at least one feedback channel to a wireless terminal in a MIMO-OFDM system, the method comprising:

a base station transmitting to the wireless terminal in a data frame;

1) a unique identifier of feedback channel resources including at least one feedback channel assigned to the wireless terminal;

2) a location of the feedback channel resources in the data frame;

3) a total number of the at least one feedback channels included in the feedback channel resources associated with the unique identifier;

4) for each of the at least one feedback channel of the feedback channel resources associated with the unique identifier, the base station transmitting to the wireless terminal;

i) a feedback type to be transmitted by the wireless terminal to the base station;

ii) a feedback channel type to be transmitted by the wireless terminal to the base station;

iii) if the feedback type is a MIMO mode or permutation mode feedback type, a feedback cycle for transmitting feedback information pertaining to a transmission channel between the base station and the wireless terminal.

18. The method of claim 17, wherein the base station transmitting comprises transmitting the unique identifier, the location, the feedback type, and the respective feedback cycles in a format of a channel allocation information element.

19. The method of claim 18, wherein the channel allocation information element comprises a following format:

Syntax Size in bits Notes CQICH Enhanced Alloc IE( ) {  

Extended-2 UIUC 4 Identifies type of IE  

Length 4 Length in bytes of following fields  

CQICH ID variable Index to uniquely identify the CQICH resource assigned to the MSS  

Period (=p) 2 A CQI feedback is transmitted on the CQICH every 2{circumflex over ( 

)}p frames  

Frame offset 3 The MSS starts reporting at the frame of which the number has the same 3 LSB as the specified frame offset. If the current frame is specified, the MSS should start reporting in 8 frames  

Duration (=d) 3 A CQI feedback is transmitted on the CQI channels indexed by the CQICH ID for 10 ×

2{circumflex over ( 

)}d frames. If d==0b000, the CQICH is de- allocated. If d == 0b111, the MSS should report until the BS command for the MSS to stop.  

CQICH Num 2 Number of CQICHs assigned to this CQICH ID is (CQICH Num +1)  

for (i=0;

i <

CQICH Num+1;

i++) {  

Feedback type 4 0b000-0b010 = Fast DL measurement/Default Feedback depending on CQICH types 0b011 = Quantized precoding weight feedback 0b100 = Index to precoding matrix in codebook 0b101 = Channel Matrix Information 0b111 = MIMO mode and permutation mode feedback 0b110= Reserved  

Allocation index} 6 Index to the fast feedback channel region marked by UIUC = 0  

CQICH Type 3 0b000 = 6-bit CQI, 0b001 = DIUC-CQI, 0b010 = 3-bit 0b011 = 4-bit 0b100 = 5 0b101-0b111 = reserved A DIUC-CQI is a CQI channel that uses a modulation and coding level derived from the DIUC.  

if (Feedback type == 0b111) {  

 

MIMO permutation 00 = No MIMO and permutation mode feedback cycle} feedback 01 = the MIMO and permutation mode indication shall be transmitted on the CQICH indexed by the CQICH ID every 4 frames. The first indication is sent on the 8th CQICH frame. 10 = the MIMO mode and permutation mode indication shall be transmitted on the CQICH indexed by the CQICH_ID every 8 frames. The first indication is sent on the 8th CQICH frame. 11 = the MIMO mode and permutation mode indication shall be transmitted on the CQICH indexed by the CQICH ID every 16 frames. The first indication is sent on the 16th CQICH frame.  

Padding variable The padding bits are used to ensure the IE size is integer number of bytes. }

20. A method in a base station for enabling feedback in an uplink transmission of a closed-loop communication system from at least one wireless terminal to a base station, the method comprising:

transmitting a request for feedback information and an allocation of uplink resources comprising at least one feedback channel in one or more data frames on which the at least one wireless terminal is to transmit the requested feedback information to the base station;

receiving the feedback information in accordance with the request on the at least one allocated feedback channel in the one or more data frames, until all the requested feedback information is received by the base station.

21. The method of claim 20 wherein an allocation of uplink resources on which the at least one wireless terminal is to transmit the feedback information comprises dynamically allocating at least one feedback channel to the at least one wireless terminal in a MIMO-OFDM system, the method comprising:

a base station transmitting to the at least one wireless terminal;

a) an indication of a total number of feedback channel resource assignments for the one or more data frames;

b) for each feedback channel resource assignment of the total number of feedback resource assignments, the base station transmitting;

i) an identifier for a respective wireless terminal for which the feedback channel resource assignment is being assigned;

ii) a location of the feedback channel resources in the one or more data frames;

iii) if a feedback channel is currently not de-allocated, the base station transmitting;

a total number of feedback channels allocated to the respective wireless terminal associated with the identifier;

a format index for indicating a type of feedback information pertaining to a transmission channel between the base station and the respective wireless terminal.

22. The method of claim 21, wherein the base station transmitting comprises transmitting the indication of the total number of feedback channel resource assignments, the identifier, the location, the total number of feedback channels, and the format index in a format of a channel allocation information element.

23. The method of claim 22, wherein the channel allocation information element comprises a following format:

Size in Syntax bits Notes MIMO CQICH Alloc IE ( ) {  

Extended UIUC 4 Identifies type of IE  

Length 4 Length in bytes of following fields  

Num Assignments 5 Number of assignments in this IE  

For (i=0;

i <

Num Assignments;

i++) {  

CID 16 MSS basic CID  

Duration(d) 3 The CQICH is assigned to a MSS for 10 ×

2^d frames;

If d = 0b000, the CQICH is deallocated;

If d = 0b111, the MSS shall report feedback information using the assigned resource until the BS commands for the MSS to stop  

Frame offset 3 The MSS starts to provide MIMO feedback at the frame number which has the same 3LSB as the specified frame offset. If the current frame is specified, the MSS shall start transmit feedback in 8 frames.  

If (d != 0b000){  

 

Num CQICH Allocation 4 Number of CQICHs allocated to the MSS identified by the MSS basic CID₌₌  

 

Num MIMO feedback 3 Number of feedback values formatted based on the “

Format index”

field defined below  

 

Length of band index 3 Indication of the length of AMC band index  

 

Length of CQI value index 2 Indication of the length of CQI value index 0b00;

4 bits 0b01;

5 bits 0b10;

6 bits 0b11;

reserved  

 

Format Index 3  

}  

} }

29. The method of claim 21, wherein the format index is selected from one of the following format indices:

Format index Feedback contents 1. STTD/BLAST diversity STTD/BLAST selection (1 bit) + Average CQI (the permutation number of bits = length of CQI value index indicated in the corresponding MIMO CQICH Alloc IE, e.g., 4/5/6 bits) 2. STTD/BLAST antenna STTD/BLAST selection (1 bit) + Antenna group index (2 permutation bits) + average CQI (the number of bits = length of CQI value index indicated in the corresponding MIMO CQICH Alloc IE, e.g., 4/5/6 bits) 3. STTD/BLAST for AMC band Layer index (2 bits) + AMC band index (number of bits = permutation Length of band index indicated in the corresponding MIMO CQICH Alloc IE) + CQI (the number of bits = length of CQI indicated in the corresponding MIMO CQICH Alloc IE, value index e.g.. 4/5/6 bits) 4. Feedback Channel H for AMC Layer index (2 bits) + H (xx bits-depending on antenna band permutation configuration) 5. Feedback transmission Layer index (2 bits) + W (xx bits-depending on antenna weights for AMC band configuration + CQI (the number of bits = length of CQI permutation value index indicated in the corresponding MIMO CQICH Alloc IE, e.g.. 4/5/6 bits) 6. Feedback V matrix for AMC Layer index (2 bits) + V (xx bits-depending on antenna band and permutation configuration) + CQI (the number of bits = length of CQI value index indicated in the corresponding MIMO CQICH Alloc IE, e.g., 4/5/6 bits)

24. A method for enabling feedback in an uplink transmission of a closed-loop communication system from a wireless terminal to a base station, the method comprising:

the wireless terminal transmitting a message comprising feedback content, the format of the feedback content determined by a format index that is an indication of a respective transmission format of the feedback content.

25. The method of claim 24, wherein the message comprises a following format:

Size in Syntax bits Notes MIMO Feedback Response message format ( ){  

Num MIMO feedback 3 Number of feedback values formatted based on the Format index defined below  

Format index 3  

for ( i=0;

i <

Num MIMO If the Num MIMO feedback >

 

feedback;

i++) 1, the feedback, either layer based or AMC band based, shall be in the order so that the layer or AMC band who has the maximum COJ appears first.  

{ Feedback content formatted 3 as indicated by format index If (Format index ==

     4) Average interference 4 Average interference If (Format index ==

     3) STTD/BLAST Selection 1 0b0;

STTD selected 0b1;

BLAST selected }

26. The method of claim 24, wherein the wireless terminal transmitting a message comprising the feedback content occurs in response to a message received by the wireless terminal requesting the wireless terminal to transmit the feedback content based on a requested format index.

27. A method for enabling feedback in an uplink transmission of a closed-loop communication system from a wireless terminal to a base station, the method comprising:

the base station transmitting a request message for feedback to be received from the wireless terminal, the format of the feedback determined by a format index that is an indication of a transmission format of the feedback content.

28. The method of claim 27, wherein the request message has a following format:

Size in Syntax bits Notes MIMO Feedback Request message format ( ) {  

Num MIMO feedback 3 Number of feedback values formatted based on the Format index defined below  

Length of band index 3 Indication of the length of AMC band index  

Length of CQI value 3 Indication of the length of CQI value  

index index  

Format Index 3 }